Implantable medical systems include implantable stimulators that are positioned at an implantation site and implantable medical leads that extend from the implantation site to a target site within the body of a patient. The implantable medical leads have a proximal end that is coupled to the implantable stimulator and have a distal end that includes electrodes at the target site. The implantable medical leads include conductors within a lead body, and these conductors carry electrical stimulation signals from the electrical stimulator to the electrodes to deliver the electrical stimulation signals to the tissue at the target site.
An issue that occurs for a period of time immediately following implantation of the medical lead involves the distal end of the lead being displaced from the target site due to certain bending movements of the patient prior to the distal end of the lead being adequately encapsulated by tissue growth. To address this displacement issue, during implantation a strain relief loop is created with the lead in order to allow the patient to move while allowing the distal end of the lead to remain positioned at the target site. However, the strain relief loop may experience encapsulation from tissue growth prior to the distal end of the lead being adequately encapsulated by tissue. This encapsulation of the strain relief loop limits the ability of the strain relief loop to function properly to maintain the position of the distal end of the lead.